2010 Cadillac CTS Sedan AWD V6-3.6L Page 496

2010 Cadillac CTS Sedan AWD V6-3.6L Page 496

1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.

2. Test for infinite resistance between the signal terminal C and the ground terminal B with the switch in the open position.

瀚慖f not the specified value, replace the rear compartment lid latch.

3. Test for less than 2 ohms between the signal terminal C and the ground terminal B with the switch in the closed position.

瀚慖f greater than the specified range, replace the rear compartment lid latch.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Rear Compartment Lid Latch Replacement (See: Body and Frame/Doors, Hood and Trunk/Trunk / Liftgate/Trunk / Liftgate Latch/Service

and Repair)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming

B2508

DTC B2508 or B2509

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptors

DTC B2508 01

- Seat Heater Relay Circuit Short to Battery

DTC B2508 02

- Seat Heater Relay Circuit Short to Ground

Diagnostic Fault Information

Circuit/System Description

The driver and passenger seat heating elements are controlled by a common high current relay internal to the memory seat module (MSM) and by

individual low side element control circuits. The MSM connects the heated seat heater element supply voltage circuits for both seats to a common

reference point. This reference point is biased to approximately 2.5 V. Before the MSM will allow heated seat operation, it checks to see if this

reference voltage is shorted to ground or voltage. Once the module verifies that it is not closing to a shorted heating element, it allows for heated

seat operation. The module will then continue to monitor the heating elements for a shorted circuit.